Model numbers - DDLT003 and KDLT003 Serial numbers - 85967 52020 - 85967 53040 - 85967 51050 - 85967 51040 Item type - D4R and D4S Xenon Ballast Control Unit Module Quantity - 1 piece Key attributes - A specific ballast control unit module with multiple identification numbers and characteristics - Designed to manage Xenon ballast operation for D4R and D4S headlamps - Provides power delivery, timing control, and fault detection for reliable lamp performance Compatibility and performance - Compatible with D4R and D4S Xenon lighting systems - Serves as an OEM-style control unit module for replacement or repair scenarios Use scenarios - Replace a failed Xenon ballast control unit in a vehicle with D4R or D4S headlights - Use in repair or restoration projects requiring D4R/D4S compatibility - Keep as a spare part for service operations or fleet maintenance of Xenon headlamp systems